stm32f103r6串口发送和接收指令串口助手输入a点亮b熄灭代码

下面是一个简单的示例代码，使用USART1串口模块发送和接收指令，当接收到字符'a'时点亮LED，当接收到字符'b'时熄灭LED。

#include "stm32f10x.h"

void USART1_Init(void);
void LED_Init(void);
void USART1_SendChar(char ch);
char USART1_ReceiveChar(void);

int main(void)
{
    char cmd;

    USART1_Init();
    LED_Init();

    while(1)
    {
        cmd = USART1_ReceiveChar();
        if(cmd == 'a')
        {
            GPIO_SetBits(GPIOA, GPIO_Pin_0);  // 点亮LED
        }
        else if(cmd == 'b')
        {
            GPIO_ResetBits(GPIOA, GPIO_Pin_0);  // 熄灭LED
        }
    }
}

void USART1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_USART1, ENABLE);

    // USART1 Tx (PA9) pin configuration
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // USART1 Rx (PA10) pin configuration
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // USART1 configuration
    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    // Enable USART1
    USART_Cmd(USART1, ENABLE);
}

void LED_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);

    // Configure LED (PA0) pin
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    // Turn off LED
    GPIO_ResetBits(GPIOA, GPIO_Pin_0);
}

void USART1_SendChar(char ch)
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    USART_SendData(USART1, ch);
}

char USART1_ReceiveChar(void)
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_RXNE) == RESET);
    return USART_ReceiveData(USART1);
}

在使用串口助手发送字符时，需要选择9600波特率，8位数据位，无奇偶校验位，1位停止位。